| 摘要 |
An apparatus includes a processor, a computer memory, a user interface, and computer-executable instructions which enable a user to formulate mathematical expressions via the user interface. The mathematical expression is composed from objects selected from a library of object types in the memory. The object types include primitive objects and non-primitive objects. Non-primitive objects contain at least one field which in turn can contain additional objects; primitive objects have no fields. The mathematical expression is defined by a computer-readable data structure in the memory, and each object and field has a mathematical significance assigned thereto. The data structure uniquely identifies each object and each field, and includes pointers to define nesting of the objects and fields in the mathematical expression. The computer-executable instructions include steps to identify user inputs with at least some of the objects, and to display the mathematical expression represented by the data structure via the display. |
